Method for applying a forming lubricant to glass fibers



United States Patent 3,287,096 METHOD FOR APPLYING A FORMING LUBRICANT T0 GLASS FIBERS Alfred Marzocchi, Cumberland, KL, and Gerald E.

Rammel, North Attleboro, Mass., assignors to Owens- Corning Fiberglas Corporation, a corporation of Delaware No Drawing. Filed June 21, 1965, Ser. No. 465,765 1 Claim. (Cl. 65-3) v The present invention relates to lubricants of the type which are applied to glass fibers immediately after forming to protect the individual filaments from abrasion during subsequent movement over mechanical parts, twisting and weaving operations.

Glass fibers are made by pulling molten glass streams flowing through tiny orifices in orifice plates. The orifice plates contain conventionally a hundred or more orifices, usually in multiples of 204, and molten glass passing through each of the orifices is quickly stretched to reduce the size of the filaments. Thereafter the filaments are gathered together in an untwisted strand and wrapped upon a tube or spool to form a package. Glass fibers easily abrade each other, and during the gathering together of the 204 or more filaments, it has been conventional to apply some type of carbonaceous material to protect the filaments from each other and thereby reduce breakage of the filaments during subsequent passage through the high speed machinery used in twisting and weaving operations. After the filaments are gathered together and wound upon a tubular form, the tubes of untwisted fibers are removed from the forming machines and moved to twisting machines wherein the untwisted strands are passed over apparatus which twists the filaments together and again winds them on a tubular form.

In those instances where Woven fabrics are to be produce, a plurality of spools of twisted fibers are installed in conventional weaving machines and a fabric of the desired pattern is produced. The woven fabric is then placed in ovens to burn off the carbonaceous lubricant and soften the fibers to set the pattern of the weave, provide drape, and give the fabric a permanent shape. After the lubricant is burned off, the woven fabric is sized and sold for subsequent tailoring operations.

It is of the utmost importance that all of the lubricant be completely removed in the burning process inasmuch as remaining carbon produces discoloration of the dyed fabric. It has been found that between 1 and 2% of the forming lubricant is sufficient to protect the fibers during handling up through the weaving operation, and it has also been found that the percentage of lubricant must not vary appreciably, or exceed 2% if discoloration of the heat cleaned and finished woven fabrics is to be avoided.

The spools of untwisted strands of filaments which are initially produced will contain thousands of yards of strands Wound on top of itself to a thickness of approximately 2 inches or more. A sufficient length of time expires between the initial winding operation and the subsequent twisting operation, and during this time, a large amount of water evaporates from the' spool, and in some instances, the spools are completely dried. During this drying operation, water from the center fibers migrate to the outside surface of the spool, and a certain amount of movement of the carbonaceous lubricant-binder accompanies this migration of the water. The result is that the filaments on the outside of the package may contain from 5 to 6% of the lubricant whereas the filament at the center of the package will only have from 1 to 2%. It has been accepted practice heretofore to destroy from 1200 to 2500 yards of strand from each wound spool,

and to only use the center portion of each spool for' the weaving of textiles which are to be finished. The migration of carbonaceous lubricants is, therefore, a serious problem, and the loss of the outside coils of strands on each spool has made woven glass fabrics expensive.

The carbonaceous lubricants which have been used heretofore have included either a hydrolyzed starch such as dextrin, or a reaction product of starch such as ethylated starch in order to be sure that none of the original starch granules remained. Starch granules vary so greatly in size and in composition as to make it very difiicult to produce a homogeneous material which can be properly applied to fibers without producing uneven distribution in the wound packages. In addition, these materials gel readily, and if a glob of gel reaches the spool and is wound in place, spaced-apart regions of high carbon concentration are produced. In addition, granules may cause uniform viscosity throughout a batch and, therefore, uneven application upon the fibers, and prior to the present invention, it has not been possible to use whole starch or its fractions as a forming lubricant-binder.

According to the present invention, a process is provided wherein amylopectin at a concentration considerably below that normally used in prior art forming lubricant solutions is used without encountering uneven deposition in the winding operation. Globules of gel are not formed in the wound package and it has been found that the deposition is considerably more uniform than when dextrin or reacted products of starch are used as the lubricant. It has been found that considerably less broken filaments are produced in the Winding operation and subsequent handling than when dextrin or the reacted products of starch are used as the lubricant.

The characteristics of amylopectin solutions are considerably different than the characteristics of either dextrin solutions or solutions of the reacted products of starch. Dextrin solutions must be applied to fibers at a temperature of between and F. in order that they will be sufiiciently mobile to produce a uniform coating. Amylopectin solutions in order to have the same viscosity at a temperature of 120 to 140 F., requires a concentration of amylopectin of above approximately8% by weight. An 8% by weight solution of amylopectin when applied to the untwisted strands of glass produces such a stiff strand that the coated materials do not flex properly during subsequent bending. Solutions of amylopectin capable of being applied at a'temperature of between 120 and 140 F. cause the filaments to undergo breakage and have too high a fuzz level. It is not possible to apply solutions of amylopectin of a concentration less than approximately 5% at a temperature of 120 to 140 F. in a manner which is sufficiently uniform to prevent some portions of the strand from breaking due to lack of sufiicient lubricant.

Amylopectin is the highly branched fraction of naturally occurring starches. Since amylopectin is highly branched, it is more soluble than the non-branched amyl-ose fraction of starch, and the molecules have greater mobility in water and do not gel as easily. According to the invention, it has been found that cationic organic materials, particularly those containing an amine radical, will hydrogen bond to the oxygen of the OH groups of the amylopectin molecule and thereby prevent or greatly retard cross-linking of the molecules. It has further been found that the OH groups on the surfaces of glass present a stronger bonding force with respect to the cationic organic materials than do the starch molecules, and that the glass will, in fact, remove these cationic materials from the starch molecules and thereby leave the starch molecules free to regroup in situ around the glass fibers to produce a very uniform film. This phenomenon is believed to explain why amylopectin forms better films 3 on the glass fibers than does dextrin and the reacted prod.- ucts of starch, and also further explains why a smaller concentration of amylopectin can be used than can be used of the prior art dextrin or reacted products of starch. This film is sufficiently bonded to hold broken fibers in place, and this is also believed to contribute to the low fuzz level which is achieved. It is believed that the cationic materials are only removed from the starch molecules adjacent the surfaces of the glass and that the cationic materials on the amylopectin molecules adjacent the outer surfaces of the coatings, remain in place at least until some future time. This provides a measure of lubricity adjacent the exterior surfaces of the coating which helps to separate the coated strands and provide an improved lubrication during subsequent movement over stationary surfaces. This phenomenon also helps in reducing the fuzz level below that of strands coated with dextrin or the reaction products of starch. It has further been found that the amount of cationic materials, as for example, cationic lubricants which are used with amylopectin must be controlled within narrow limits, and that if the amount used exceeds approximately .003 mol per 6 parts of amylopectin, a material which is too soft and mushy and which does not bond together properly is formed. It is believed that too high a mole content of the cationic materials provide too great an amount of cations for the glass to hydrogen bond with and, therefore, the cations are not suificiently removed from the layer of amylopectin surrounding the glass to allow the amylopectin to cross-link and form a proper film. In order that a proper film of amylopectin can be provided, it has been found that it must contain between approximately 2 parts and 6 parts of amylopectin per 95 parts of water and be at a temperature of between 70 and 100 F. The solution must contain between approximately 0.0003 to approximately 0.003 mol of a cationic lubricant that has been thoroughly mixed with the amylopectin solution. Other materials such as non-ionic lubricants emulsifying agents and plasticizers can be used to produce their desired effects without destroying the essential film-forming properties of the amylopectin-cationic lubricant solution. While the amount of emulsifying agent used is not-critical, it has generally been found that between approximately 0.1 to 1 part by Weight is sutlicient.

The cationic materials used are preferably amines of fatty acids in order that they will provide lubrication in addition to contribute to the above described film forming function.

An object of the present invention is the provision of a new and improved glass fiber having a dry lubricant coating which is flexible and which has a uniform film of carbonaceous lubricant particles loosely bonded to each other surrounding the glass fibers.

Another object of the invention is the provision of a new and improved glass coated fiber of the above described type wherein the lubricant is amylopectin bonded together in situ surrounding the glass fiber.

Another object of the present invention is the provision of a new and improved process for providing a coating of lubricant on glass fibers which can be carried out at ambient temperatures and conditions.

Another object of the invention is the provision of glass fibers coated with a dry lubricant and which are less susceptible to breakage during twisting and weaving than are prior art coated fibers.

The aforementioned objects are achieved by the present invention through the employment of compositions containing an amylopectin fraction of starch as a principal ingredient.

The starch fractions are obtained from common starch granules which are composed of an outer envelope of amylopectin having the following structure:

which usually comprises 20-26% of the total composi tion and has the structure:

in which N averages 400-700. These constituents may be separated by fractionating techniques, such as those disclosed by US. 2,829,987, 2,829,988, 2,829,989 and 2,829,990.

The amylopectin fraction of starch has proved highly satisfactory in the practice of the invention. Amylopectin enhances the processing characteristics of fiber glass strands and yarns treated therewith by reducing fuzz. level, providing uniform tension characteristics, enhancing breaking strengths and greatly diminishing the existence of color bands. Amylopectin also has the added advantage of being more readily dissolved in water, thus obviating the necessity for heating-or cooking. In the present invention it should be noted that the term cooking is not intended to connote particle breakdown with attendant conversionof the material to the form ofa solution.

Experimentation has shown that preferred results are achieved when the starch fraction is employed in a proportion ranging between 26% by weight of the total composition or between 25-88% by weight of the nonaqueous or non-carrier constituent of the composition.

' The compositions of the invention may be enhanced by the addition of other materials such as emulsifiers,

lubricants, additional film-forming material, oils, plasticizers, etc. The compositions are preferably applied in a water base although equivalent materials may also be used. Suggested ranges for the aforementioned additives.

Lubricant-softeners, 0.0003-.003 mol.

While animal or vegetable oils are preferred, any oleaginous material may be employed as the lubricant.

Although polyvinyl alcohol or gelatin is preferred as.

the supplemental film-forming materials, other filmformers such as copolymers of acrylonitrile and styrene,

vinyl chlorides and acetates, vinyl chlorides or nitriles; cel-.

lulose derivatives such as acetates, nitrates and alkyl cellulose; polyamides; polyalkylenes and their halogenated derivatives; vinyl compounds; polystyrene and the acrylates may be used.

Lubricant-softeners employed are preferably cationic materials such as condensates of tetraethylene pentamine with stearic or pelargonic acid which are solubilized with acetic acid. In addition, the chlorides, acetates, bromides,

dibasic acid salts and other salts of other primary, secondary and tertiary amines, quaternary ammonium compounds, and of phosphonium and sulphonium compounds are applicable. 1

While polyalkyle'nel glycols have been found efficient in the role of plasticizers, other compounds such as the fatty esters of the glycols, organo phosphates such as tricresyl phosphate, phthalic acid derivatives, chlorinated paraflins, other glycol and glycerol derivatives and the esters or derivatives of the following acids: adipic, fumaric, maleic, oleic, azelaic, benzoic, citric, sebacic, phosphoric, ricinoleic, stearic, sulfonic and tartaric, may also be used.

Although polyoxyalkylene compounds such as polyoxyethylene sorbitan monooleate are preferred as the surfactant-emulsifier, other equivalent compounds exhibiting similar functional characteristic are also capable of utilization and the amount used does not appear to be critical.

The following examples set forth preferred formulations for compositions with which highly satisfactory results have been achieved:

EXAMPLE 1 Parts by weight Water 95 Amylopectin 5 Vegetable oil 2 Polyoxyethylene sorbitan monooleate 0.21 Polyethylene glycol 0.5 Octadecyl amine acetate, 0.00076 mol.

EXAMPLE 2 Water 95 Amylopectin 5 Vegetable oil 2.12 Polyoxyethylene sorbitan monooleate 0.06 Gelatin 0.06 Polyvinyl alcohol 0.09 Octadecyl amine acetate, 0.00064 mol.

EXAMPLE 3 Water 95 Amylopectin 5 Vegetable oil 2.0 Polyoxyethylene sorbitan monooleate 0.2 Octadecyl amine acetate, 0.001 mol.

EXAMPLE 4 Water 95 Amylopectin Vegetable oil 2.0 Polyoxyethylene sorbitan monooleate 0.2 Dodeco-ethylene diamine, .002 mol.

EXAMPLE 5 Water 93 Amylopectin 7.0 Vegetable oil 2.0 Polyoxyethylene sorbitan monooleate 0.2 Octadecyl amine acetate, 0.001 mol.

EXAMPLE 6 Water 95 Amylopectin 5 6. Vegetable oil 2.0 Polyoxyethylene sorbitan monooleate 0.2 Octadecyl amine acetate, 0.004 mol.

Example 3 is a preferred compositionof the lubricantbinder material. Example 4 is a composition giving a thin but uniform coating. Example 5 gives a lubricantbinder material which is too viscous at a temperature between 70 and F. to be applied properly. This viscous material does not coat all of the areas of the fibers, so that breakage is experienced during subsequent forming. Example 6 is an example of a material having too high a content of the cationic lubricant. The material of Example 6 when applied to the fibers is so soft and mushy that it does not adequately protect the fibers during twist: ing and weaving, and so the resulting materials have too high a fuzz level.

The above compositions are prepared by slowly adding the amylopectin to approximately 25 parts of water at room temperature (approximately 70 to 100 F.) with continuous agitation. The cationic lubricant is dissolved separately in approximately 5 parts of water and the solution of the cationic lubricant is then added to the amylopectin solution while the amylopectin solution is agitated. The emulsifying agent is added to the non-ionic lubricant and the mixture is added to 25 parts of water at room temperature with strong agitation. This material is thereafter added to the amylopectin solution with agitation. The polyvinyl alcohol, gelatin, or other film former if used is dissolved separately in approximately 25 parts of water and then added to the amylopectin solution with agitation. Thereafter the remainder of the indicated water is added to provided the desired concentration of amylopectin, and the pH is adjusted to 4.0 plus or minus 0.2 with acetic acid. Other acids can be used.

Application may be accomplished by any conventional method and satisfactory results have been reached with a standard apron applicator, of the general type disclosed by US. 2,873,718. In addition, pad type applicators such as those disclosed in US. 2,373,078, 2,390,370 and 2,392,805, or roller type applicators may be employed. Broadly, the lubricant film-forming compositions of the invention may be applied at forming, or immediately subsequent thereto, through the use of conventional contact, spraying or immersion application apparatus. As disclosed in the above patents, the coating materials are applied to the individual filaments before they are grouped into a strand.

Excellent products have been achieved when the surfaces of structures such as glass fiber strands or yarns are coated with the compositions of the persent invention. Wound packages of yarn coated therewith have been marked by substantial reduction of the migration of the coating compositions to the surface of the packages. In addition, the products treated in this fashion are characterized by reduced fuzz level, uniform tension characteristics, enhanced breaking strengths and freedom from color banding.

In addition to the solvents, plasticizers, oils film-forming materials, emulsifiers and lubricants set forth in the examples provided in the specifications, any equivalence known and/ or utilized in the art may be substituted without departing from the invention.

It is understood that various changes, substitutions, additions or deletions may be made in the formulations of the compositions of the present invention as Well as in methods for the preparation or utilization, and in the products achieved through such utilization without departing from the spirit of the invention, particularly as defined in the following claim.

We claim:

A method of making glass fiber bundles to reduce breakage during fabrication processes such as twisting, said method comprising: drawing out molten glass into fibers and promptly coating said fibers with a solution maintained at from approximately 70 F. to approximately 100 F. and consisting essentially of the following:

Parts by weight Water 95 Amylopectin, approx. 5

Nonionic lubricant, approx. Octadecyl amine acetate, between approx. 0.00064 and 0.001 mol.

collecting the fibers into a bundle; drawing the wetted bundle of glass fibers through air at ambient temperature with attendant windage and loss of moisture; and

winding the coated bundle of glass fibers on a spool ,with the wraps in tight engagement with each other.

References Cited by the Examiner UNITED STATES PATENTS 10 DONALL HpSYLVESTER, Primary Examiner.

R. L. LINDSAY, Assistant Examiner. 

